crate vs packing case

crate and packing case both are nouns.

Word	Noun	Adjective	Verb	Adverb
crate	Yes	No	Yes	No
packing case	Yes	No	No	No

As nouns, packing case is a hyponym of crate; that is, packing case is a word with a more specific, narrower meaning than crate:

crate: a rugged box (usually made of wood); used for shipping
packing case: a large crate in which goods are packed for shipment or storage

Other hyponyms of crate include packing box, soapbox.

crate (noun)	packing case (noun)
a rugged box (usually made of wood); used for shipping	a large crate in which goods are packed for shipment or storage
the quantity contained in a crate

crate (verb)	packing case (verb)
put into a crate; as for protection